1. Field of the Invention
The present invention relates to a data output apparatus having output means of outputting a plurality of types of data, a data input apparatus having input means of inputting a plurality of types of data, and the like.
2. Related Background Art
Currently, there has been proposed a recording and reproducing apparatus having a function of recording a plurality of types of stream data on a magnetic tape and a function of reproducing a plurality of types of stream data from a magnetic tape (for example, Document 1 described below). In the Document 1, there has been proposed a recording and reproducing apparatus, which records a SD (Standard Definition) video data or a HD (High Definition) video data on a magnetic tape. Here, the SD video data is a vide data which conforms to a DV system formulated by a HD Digital VCR Conference, and the HD video data is video data conformed to a MPEG-2 system.
Also currently, in the network interface of the recording and reproducing apparatus, there have been known IEEE 1394 standards (see Documents 2 and 3), and USB standard (see Document 4). Either of the IEEE 1394 standards and the USB standard is a standard regarding a high-speed serial bus. In particular, in the network interface (hereinafter referred to as IEEE 1394 interface) conformed to the IEEE 1394 standards, it is possible to control input and output of the stream data conformed to the DV system or the MPEG-2 system (see Document 5 to 7). Hereinafter, the stream data (including audio and video data) conformed to the DV system is referred to as “DV data”, and the stream data (including audio and video data) conformed to the MPEG-2 system is referred to as “MPEG-2 data”.
Respective documents referred to as described above are as follows.
Document 1: Japanese Patent Application Laid-Open No. 2001-275076
Document 2: IEEE Std 1394-1995, IEEE Standard for a High Performance Serial Bus, Institute of Electrical and Electronics Engineers, Inc.
Document 3: IEEE Std 1394a-2000, IEEE Standard for a High Performance Serial Bus—Amendment 1, Institute of Electrical and Electronics Engineers, Inc.
Document 4: Universal Serial Bus Specification Revision 2.0, Apr. 27, 2000
Document 5: IEC 61883-1: Consumer audio/video equipment—Digital interface—Part 1: General
Document 6: IEC 61883-2: Consumer audio/video equipment—Digital interface—Part 2: SD-DVCR data transmission
Document 7: IEC 61883-4: Consumer audio/video equipment—Digital interface—Part 4: MPEG2-TS data transmission
In the case of a recording and reproducing apparatus having an IEEE 1394 interface and conforming to the IEC 61883-1, IEC 61883-2 and IEC 61883-4, it is possible to continuously output DV data and MPEG-2 data to the outside through an oPCR defined by the IEC 61883-1, and also continuously receive DV data and MPEG-2 data from the outside through an iPCR defined by the IEC 61883-1.
Depending on a control apparatus for remote-controlling the above described recording and reproducing apparatus, there are some cases where it would be better to lock a data format of the stream data outputted from the oPCR of the recording and reproducing apparatus to a predetermined data format. For example, when the control apparatus can process the DV data, but cannot process the MPEG-2 data, a data format of the stream data outputted from the oPCR would be better to be locked to the DV system.
However, at present, there has been no command clearly defined, which requests to change an oPCR state to a locked state (a state locked to a predetermined data format (either of the DV system, the MPEG-2 system, and the like)). There has been also no command clearly defined, which requests to change the oPCR state to an unlocked state (state in which a locked state is released). Consequently, from the control apparatus, the oPCR state cannot be changed into the locked state or the unlocked state. Further, in case there exist a plurality of control apparatuses, it is also not clearly defined as to which command from the control apparatuses should be given a priority. These problems also hold true for the command which requests that the data format of the stream data inputted to the iPCR is locked to a predetermined data format.
Further, these problems are also problems occurable also in the recording and reproducing apparatus having output means (including not only a logical output terminal such as the oPCR, but also a physical output terminal) which is equivalent to the oPCR defined by the IEC 61883-1, and still also problems occurable in the recording and reproducing apparatus having input means (including not only a logical input terminal such as the iPCR, but also a physical input terminal) which is equivalent to the iPCR defined by the IEC 61883-1.